SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e698463ec51ebd86a52c45e50da7bcd0dd99455ef75519be152a34e6fa04374' 
  AND token = 'eaRO5TNWrIPP5S3wUSpgKGhXrafek5+SLd13kimdEKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}