SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '127422dd41faf107f8cf01e6bf947af6cf2be144edd4b2ac362fb50680761f0a' 
  AND token = 'mDMSQwFL9MRMdSlAllPeypDFqGsOBmFEJ7t4P3/iqCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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