SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eccdf9726eafda2cec8e73f6165d48721c5b2d3478cf8927e4fbcb40dfdfe99d' 
  AND token = 'OQKq6H3x7yXInZ9Y3ogmm4tT8mpsvbp5zHaIeAxKjIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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