SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cebd795929c115f9ba8d3b2b4823cecc7f56109f24bccd12c5807e95a6aced86' 
  AND token = 'pYwJoRal49DyCS2sY5Ir8HCCc+2Mlj2xuWaS9A9aaDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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