SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4252f581771052350881b1c512268afdf8621787d70bea840f32c19b7bdfaea0' 
  AND token = 'akOO0Mo5HoSmvCJ2zPejrh96RdYgE8EognUq5Tm1YFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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