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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ac9c3a52c95a0df3af006e2ae67813b81205df397b3d9ab1d8d1ad5c6cdaa9b' 
  AND token = 'm6mcpwzERenVQklxFQ8toot/2e/QHTlDk7jzUQ1HSpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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