SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0348877835d2995c7f875043f44201f316f06fe4034f7afcd9d894bb07875b4e' 
  AND token = 'oryuuA9vGJ2jwI1CaBTyRngEeTF2t81mhj7hwJhThdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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