SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca48046f28da9e6b4b309a796d47bcbe88d30a7f2304e6a9323feb086c69b993' 
  AND token = 'icIQDbNkb3dHkK3FNJnT3puone+UjTm1LxtuEVxLS14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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