SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b83aaec48a7ef0b88b47d1d357581ad9c1ed83039547e1c769eff1be627c2cc8' 
  AND token = 'G3t/HY2lyqpOQK7euL/9AVEs7QwVnGig6kEhjEivozc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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