SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '962c048ad24891f5140a885cf2c400110ed29998b4fe3dd615b05478133fd03a' 
  AND token = 'fSS93PHv5IV+cPUKcA2vfj9M7nVMhhnjml1cJzelvGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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