SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1910b8459550533c760be43d077ca967375ffd0234397856b84276f92b1fde3' 
  AND token = 'moH1DRcd+3qJ7rnXmhrp9zjCnpuabNl8btZOcUwvJJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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