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SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c35ef38c4e2a5bc6a15d01bdd66e5c50a1f83a71356999188134a07340dfc99b' 
  AND token = 'kFjEcQsGW43xCFLuOT2++oLbX+jANnFTt1+ZHJB501A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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