SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21723b78091f3b67c6b1cd52f5982069e6dc451b6669c0cacd616738f3fa4410' 
  AND token = 'qeNzxoOKldeyR+FH0KihIGzAZFQmzLDY23mjk/rfRCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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