SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23913c7d69751bb7277f1e881abf3a2f4c2e4b95e2a3da176232c64d1adaffb0' 
  AND token = '+UA9BPGm1HYMaaDik/Bwu7lAzx0DtSiepUVj+xGl1gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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