SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37d045ce575dd0c7c274175dd093ec827199c696ca052859cd10f2df441995bb' 
  AND token = '2csyZP3IAHZkTLklJslsEIjhp3vpkDVjBRAh8eryYHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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