SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f6edfb3425cf184230c84349d857bcc31ffa24c1f2bb9e438556196a26784c3' 
  AND token = '8hTy1QRiJvQPb0pLOj4k714U44zh65y0tOBeVfFk4L4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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