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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8e6fa0d8ad80f681c6786f964cd5fa15e4d284ad73dbade33beb26db2ebed8c' 
  AND token = 'MACq+IblSxwzfyVAp7v62jcCuL3oqBwscEPIsXiosXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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