SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74c14b5ce4fcb18121e50f96b11666030426a1bb974278524eb7911077c22825' 
  AND token = 'CVX4nDImi//nARqOvRpxMGLlZ1/gWq3BuMFeBqJnFAw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00083

JSON explain

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