SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec9a90d0cebe6647cd8f8ebaaf555bb95bf5f9a58ff475685fdc71ca189eec32' 
  AND token = 'bf/vp1RCmIdrgmXeEKcghoNXmv9eOAkdAVnppB6VZ+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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