SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2bbb32e608b8fa7818f05df2b6544975df482335c6f347961c9f0d3998f3d1f' 
  AND token = 'Sz7CUrlgmKN3/81FeMSwd+g9KYiggEXYCCTsWYdisHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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