SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c59147c4213dfa894ab3fe25e4483afe39c44a9f150f008def22b28816eb568d' 
  AND token = 'C/DvcUKM9vIGrLwsypYKL9euSPdEtxKmlIiT4niyCgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}