SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30e51b81cc0b4304d3461078577eebfb9886fdeaf7255a1926d3960c57245e21' 
  AND token = 'RarKjC+rOd1fENLwHqBHZRXH173+10V0gUEUvDOsGOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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