SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1097824b2dda64f44a6d0afd939703532bb8a2db063d66fa8f1dfa283dcfc786' 
  AND token = 'vR0p0jfeaUHg+KB4I8Ig1Xpq/LRP3nOUyG+iX2nz/jI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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