SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8de7b00c3c41fa9f784cee6b940dcbd607c636407e282ce9f202c985515bb1f0' 
  AND token = 'N+n9Q+XL5sCJJYDT3IK6h+Z9NUnSzKZwFlPVJpOApao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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