SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '990f17628cd66a698c3c5d99cd33a5b474957bc0477e913a2410a19ab578cc73' 
  AND token = 'qGJKst29SP/KgHy3oj65YeJ+Mlv5UoqbRL6ReCP3lew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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