SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9091522c4f5dc12351a27edfa00298d25cacac592a31bebb31f6c01e2c3bc2e' 
  AND token = 'xa4l/B4i1P8x7QUU/u12VY+f8Sx7Vc/U0Q/4MmBA4lw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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