SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8688e7b92411bd1889a0d712eac073333e7fabc464306ef27c27b5b5be41fe45' 
  AND token = 'mL9PwVmc4IhLFc9HIGUqX+ZaBGD/UPziZmhv323XyAk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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