SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '101ff86429a568f2cc307ce89f3cb1392c0b2aaa8921b14ff6a1272eadfc554a' 
  AND token = 'jwMBXhvkixgoJDt2xMtkrs95+44JW1kxqvSThaGQbL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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