SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e151f9bcd418983ce53164627eb73ff412491b32a7ffc3dab2cb72c52ba34e85' 
  AND token = 'f7NuAl35y2QxPltBsTivSw61JAmOYxVoMRpjhMnOAmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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