SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7effcc193babdbf1fb1dcbabf19a720a45de838fec169db87e042d1e6be1285a' 
  AND token = '8qU0uHJ778Uya67tDPqV7DYwYVqVcgucpsvqGwo/Aow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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