SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8532d4946823d4f255dc5c0c38022757813b3f6a1f1d966524c91febfcaccb7' 
  AND token = 'iGXGqdo6+j9PPsB9ZxMknmhsV8nH6+2FjnOXxiYEi6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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