SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b115b29c245b9c4644d6d431375051ee147ccad4f97650c28d1816f8e56959a6' 
  AND token = '5sOKFSuSB+iGevQO/+OO/R6uVYxX+M7qBMm13swM1Xk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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