SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e18037bd126df52628f186638227fecb6d5cce3742fc510d72c16327a02d2a5c' 
  AND token = 'J1BZ/SBCJXBk6g4k+vmQ/2D9ZKLlXf1YviDgA2xT+bw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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