SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9a524cede156a09694d751a64ae8e23de406c6f2289decc5b06a04a14b578d6' 
  AND token = 'sCcMaXE5tNtj8N1GalpyVZFqPtGOYpmNYTE5PJ7HBJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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