SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03550910b29942cab700c4bc04c7f91c459ad66b17826a1ab6860cc352cc482e' 
  AND token = '1i+AT1zWY/P6zMk1P1aun8mfaOB8KTZvmHfBXuRGu0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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