SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af5d2e273ff2ce0db3e956b38cdca3d275c65c8ff5f0076a25a793c2b7c5619b' 
  AND token = 'h5T+Mmdj8AGsc4gOPqDPDONFByTENuW7ASzvnVu/bKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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