SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41aedd8743d937f6aa5c09cbb3bc7693e05a236f15df86a6875f5e7c0681fb56' 
  AND token = 'pb6vJF6xRfziHGUn/XQEW0mq82IBjow+RBnciIGPTtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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