SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2af0621f8840442b08e2efab4ded5b3d67c8eb2d9db6232856a63754fa7c06c1' 
  AND token = '/ylXmyEDNG2QJZJCv+tRkSPJQ8rwv0/Tzko1lwPs+cQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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