SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '190d814e1fa483e0e278cbcefb335fe01f8cc0f06acf018dd0f5fa602c2c4e59' 
  AND token = 'uKB4OX7rup1bSDOTQVdMaIZsEWwoSPkISvBOqNPd3Y0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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