SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'baa5e2247e4b703092c1efc35dd06d908c2a66173c7f9673f471b1d95ffcdaae' 
  AND token = 'hplNRryrLk16S9bzXh0nXRD4tIKEpawCz2EdL+e2/CQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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