SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4100c67245b8ce4fda678610007e7f0f7db5d23650043254569d8fd6b142ede6' 
  AND token = '5ETp+NLPCTQwglGrGqZJvOZXnc/ReVipP9wc4LzE5q0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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