SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce29d23ef2223a84dd7f3867b958abc6f4ebc296b9bbdf7cdf3e96fdc90541b5' 
  AND token = '6fdGnVl4+AZs/Y4KQYLIZ+IWZvfJeMM0hIIBcMluv+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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