SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de5aaadbda5e9b1957a5e53665fcfec131068e937824fc28a956f2a615b2879d' 
  AND token = 'GyI5IL83dmVd1pxLsMZyO/UKWuMynHfKiK27y5TfwNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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