SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '675aef7ed6d17ab0dd73853619cbd6b7dfbe61c953afe7a667611735e525f1b9' 
  AND token = '2S2JQAkXEZIUbRXq4WOmdvoJibzgvckkZyF9fhYhyos=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}