SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6866fff94930422b66cee717f2a99f0d8240eeed3e6586b9decaa16c133b7f9' 
  AND token = 'OtuYxDidZIW0VhErPwG2bLtpfpV3hdzWljIYvzDSyL0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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